There are two websites I think you should know about. Do you find it difficult to say a word correctly? Do you want to hear the correct pronunciation(发音)? If so, what you’ve been looking for is cooldictionary.com. This site is designed to pronounce words and phrases in precise(严谨的) manner. All you have to do is to go to the Pronunciation Help and type in a word. You can also practice your spoken English and improve your communication skill.
   Another useful site is www.nutsandboltsguide.com. It has been specifically designed to help you with every step of writing. This site is a must-visit for all those who want to become a writer. It not only talks about different kinds of writing but also discusses a lot about grammar. I’m sure that this site will help you with your writing skills and different writing styles with its sound tips. So get connected and log in to play. Happy surfing!

同学们对实验“煅烧石灰石”展开深入探究．

资料：石灰石中的杂质高温不分解．

A、B、C、D、E、F、G、H八种物质，有如图所示关系：其中A是一种暗紫色固体，B是黑色固体，D能使带火星的木条复燃，E、F都是无色液体，G是木炭，H是一种能使澄清石灰水变浑浊的气体，在②的反应前后B的质量和化学性质都不改变．

请你根据上述信息，推断出下列物质．（写名称）

（1）E____、H____．

（2）写出反应①、②、③的化学方程式，并指出反应的基本类型：‚

①____ ，____ 反应；

②____  ，____ 反应；

③____ ，____ 反应．